1. Field of the Invention
The present invention relates to an apparatus for removing interference noise, adapted to a personal communication terminal having functions such as broadcast receiving and communication, and more particularly, to apparatus and method for removing interference noise in a personal communication terminal, wherein a function of removing interference noise is adapted to the personal communication terminal, and adjustment parameters for removing interference noises are continuously set to up-to-date adjustment parameters, so that, in the activation of broadcast receiving, a turn-on stabilizing time of the personal communication terminal can be reduced, and the broadcast receiving performance can be maintained at an optimum state.
2. Description of the Related Art
In general, as the public interests have recently focused upon a TV digital broadcasting, technical developments have continuously occurred to a Korean digital multimedia broadcasting (DMB) and a European digital video broadcasting (DVB).
The DMB includes a terrestrial DMB and a satellite DMB, and the DVB includes a DVB-T that allows a fixed home or office appliance to receive a broadcasting signal from a general broadcasting station, and a DVB-H that is used for a mobile phone or a mobile video appliance in consideration of low-power, mobility and portability.
With the trend of providing multi-functions to a personal communication terminal, such as a mobile phone or a personal digital assistant (PDA), so-called a TV phone, in which a TV broadcasting function is incorporated in a mobile phone, is being brought into the market of Korea, and a mobile phone incorporating a DVB-H function is ready to come forth in Europe.
Here, in the case where a single communication terminal supports two or more functions (GSM/GPRS & DVB-H), it needs a proper measure to cope with a phenomenon of reduction in receiving sensitivity of the respective appliances due to their mutual interference.
FIG. 1 is a constructional diagram of a conventional personal communication terminal. Referring to FIG. 1, the conventional personal communication terminal includes a GSM transmitter/receiver 11 for transmitting/receiving a GSM signal of approximately 900 MHz (TX: 880-915 MHz, RX: 925-960 MHz), and a DVB-H receiver 12 for receiving a DVB-H broadcasting signal having a band of approximately 470-750 MHz.
Such a conventional personal communication terminal, an influence on interference noise as that for a DVB-H receiving band corresponding to the phase noise of GSM900 transmitting band of approximately 900 MHz will be explained with reference to FIGS. 2A and 2B.
FIGS. 2A and 2B show an influence upon interference noise of the conventional personal communication terminal according to a receiving band and a transmitting band thereof. Particularly, FIG. 2A shows an influence upon interference noise of GSM900 transmitting band for DVB-H receiving band in the case where the DVB-H receiver 12 does not include, at its input, a band-pass filter for removing the GSM900 transmitting band, and FIG. 2B shows an influence upon interference noise of GSM900 transmitting band for DVB-H receiving band in the case where the DVB-H receiver 12 includes, at its input, a band-pass filter for removing the GSM900 transmitting band.
Referring to FIG. 2A, the DVB-H band ranges between approximately 470 MHz and 750 MHz, and the GSM900 transmitting band ranges between approximately 880 MHz and 915 MHz. In FIGS. 2A and 2B, it is shown that the interference noise signal of the GSM transmitting signal is introduced into the DVB-H receiving band, exerting a bad influence upon the DVB-H receiving signal.
Meanwhile, in the conventional personal communication terminal, during receiving a digital broadcasting via the DVB-H receiver 12, the situation of carrying out the GSM transmitting/receiving may occur via the GSM transmitter/receiver 11. In addition, during receiving a digital broadcasting via the DVB-H receiver 12, the situation of carrying out the GSM transmitting/receiving may also occur via other GSM transmitter/receiver positioned close thereto.
Referring to FIG. 2B, since the GSM transmitter/receiver 11 amplifies electric power of the GSM transmitting signal to high electric power of approximately +33 dBm via an internal power amplifier, such a high power GSM transmitting signal can be introduced into the DVB-H receiver 12 via an antenna. In this case, the GSM transmitting signal serves as noise in the receiving signal of the DVB-H broadcasting, so that in order to reduce such a noise, a band-pass filter (BPF) can be included in the input of the DVB-H receiver 12. The band-pass filter passes the DVB-H receiving signal of approximately 470-750 MHz, and filters the GSM transmitting signal of 880 MHz or more.
The band-pass filter included in the DVB-H receiver 12 of the conventional GSM mobile phone blocks the GSM transmitting signal, thereby improving a noise influence by an intermodulation between the GSM transmitting signal and the DVB-T signal, which occurs in an RF circuit of the DVB-H receiver 12.
However, in such a conventional GSM mobile phone, although it includes the band-pass filter, interference noise component of the GSM transmitting signal having a band of 470-750 MHz, which corresponds to a DVB-H receiving band, is not filtered by, but passes through the band-pass filter (BPF) without attenuation. This influences the DVB-H receiving band, thereby deteriorating the receiving sensitivity of the DVB-H broadcasting.